2015 YAMAHA YZ250F clutch

ENGINE REMOVAL
5-4
Removing the engine
Order Part name Q’ty Remarks
Use a suitable stand to raise the front wheel
off the ground.
Seat Refer to “GENERAL CHASSIS” on page 4-1.
Side cover (left/right) Refer to “GENERAL CHASSIS” on page 4-1.
Air scoop (left / right) Refer to “GENERAL CHASSIS” on page 4-1.
Fuel tank Refer to “FUEL TANK” on page 7-1.
Exhaust pipe and silencer Refer to “ENGINE REMOVAL” on page 5-1.
Air filter case Refer to “THROTTLE BODY” on page 7-5.
Throttle body Refer to “THROTTLE BODY” on page 7-5.
Clutch cable Refer to “CLUTCH” on page 5-35.
Shift pedal Refer to “SHIFT SHAFT” on page 5-47.
1 Engine guard 1
2 Brake pedal 1
3Spring 1
4 Cylinder head breather hose 1
5 Drive sprocket cover 1
New
New
LS
M
8
8
7
6
13
45
New
1 12
3
2
1110 9
55 Nm (5.5 mkgf, 40 ftIbf)T.R.

CLUTCH
5-35
EAS1SM5233
CLUTCH
Removing the clutch
Order Part name Q’ty Remarks
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
Brake pedal Refer to “ENGINE REMOVAL” on page 5-1.
1 Clutch cable 1 Disconnect.
2 Clutch cover 1
3Gasket 1
4 Clutch spring 5
5 Pressure plate 1
6 Push rod 1 1
7 Circlip 1
8Washer 1
9 Bearing 1
10 Ball 1
11 Push rod 2 1
New
New
New
2
3 45
(5)
(6)78961011
12
21
1
12
13
17
1819 16
15
14
13
T.R.
T.R.
T.R.
T.R.
LT
20

CLUTCH
5-36
12 Friction plate 9
13 Clutch plate 8
14 Cushion spring 1
15 Clutch boss 1
16 Thrust washer 1
17 Primary driven gear 1
18 Spacer 1
19 Bearing 1
20 Washer 1
21 Push lever shaft 1
For installation, reverse the removal proce-
dure.
Removing the clutch
Order Part name Q’ty Remarks
New
New
New
2
3 45
(5)
(6)78961011
12
21
1
12
13
17
1819 16
15
14
13
T.R.
T.R.
T.R.
T.R.
LT
20

CLUTCH
5-37
Removing the right crankcase cover
Order Part name Q’ty Remarks
Right engine guard Refer to “ENGINE REMOVAL” on page 5-1.
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
CoolantDrain.
Refer to “CHANGING THE COOLANT” on
page 3-8.
Brake pedal Refer to “ENGINE REMOVAL” on page 5-1.
Clutch cover Refer to “CLUTCH” on page 5-35.
1 Oil filter element cover 1
2 Oil filter element 1
3 Radiator pipe 2 1
4 Kickstarter lever 1
5 Right crankcase cover 1
6 Gaskets 1
7 Dowel pin 2
8Collar 1
For installation, reverse the removal proce-
dure.
T.R.
LS
New
New
67
2
5
4
1
7 8
New
3
LS
New
New
LS
NewNew
LT
LS

CLUTCH
5-38
EAS1SM5234REMOVING THE CLUTCH
1. Remove:
• Clutch boss nut “1”
• Lock washer “2”
• Clutch boss “3”
TIP
• Straighten the lock washer tab.
• While holding the clutch boss with the clutch
holder “4”, loosen the clutch boss nut.
EAS1SM5235CHECKING THE FRICTION PLATES
1. Check:
• Friction plate
Damage/wear  Replace the friction plates
as a set.
2. Measure:
• Friction plate thickness
Out of specification  Replace the friction
plates as a set.
TIP
Measure it at four points on the friction plate.
EAS1SM5236
CHECKING THE CLUTCH PLATES
1. Check:
• Clutch plate
Damage  Replace the clutch plates as a
set.
2. Measure:
• Clutch plate warpage
(with a surface plate and thickness gauge
“1”)
Out of specification  Replace the clutch
plates as a set.
EAS1SM5237CHECKING THE CLUTCH SPRINGS
1. Check:
• Clutch spring
Damage  Replace the clutch springs as a
set.
2. Measure:
• Clutch spring free length
Out of specification  Replace the clutch
springs as a set. Clutch holder
90890-04086
YM-91042
Friction plate thickness
2.90–3.10 mm (0.114–0.122 in)
Wear limit
2.85 mm (0.112 in)
34
12
Warpage limit
0.10 mm (0.0039 in)
Clutch spring free length
45.00 mm (1.77 in)
Limit
44.00 mm (1.73 in)

CLUTCH
5-39
EAS1SM5238CHECKING THE CLUTCH HOUSING
1. Check:
• Clutch housing dogs “a”
Damage/pitting/wear  Deburr the clutch
housing dogs or replace the clutch housing.
TIP
Pitting on the clutch housing dogs will cause er-
ratic clutch operation.
EAS1SM5239CHECKING THE CLUTCH BOSS
1. Check:
• Clutch boss splines
Damage/pitting/wear  Replace the clutch
boss.
TIP
Pitting on the clutch boss splines will cause er-
ratic clutch operation.
EAS1SM5240CHECKING THE PRESSURE PLATE
1. Check:
• Pressure plate
Crack/damage  Replace.
EAS1SM5241
CHECKING THE PUSH LEVER SHAFT
1. Check:
• Push lever shaft
Wear/damage  Replace.
EAS1SM5242CHECKING THE CLUTCH PUSH RODS
1. Check:
• Push rod 1 “1”
• Bearing “2”
• Washer “3”
• Push rod 2 “4”
•Ball “5”
Cracks/damage/wear  Replace.
2. Measure:
• Push rod 2 bending limit
Out of specification  Replace.
EAS1SM5243CHECKING THE PRIMARY DRIVE GEAR
1. Check:
• Primary drive gear
Damage/wear  Replace the primary drive
and primary driven gears as a set.
Excessive noise during operation  Re-
place the primary drive and primary driven
gears as a set.
2. Check:
• Primary-drive-gear-to-primary-driven-gear
free play
Free play exists  Replace the primary
drive and primary driven gears as a set.
a
Push rod bending limit
0.10 mm (0.0039 in)

CLUTCH
5-40
EAS1SM5244CHECKING THE PRIMARY DRIVEN GEAR
1. Check:
• Primary driven gear
Damage/wear  Replace the primary drive
and primary driven gears as a set.
Excessive noise during operation  Re-
place the primary drive and primary driven
gears as a set.
EAS1SM5245INSTALLING THE OIL SEAL
1. Install:
• Oil seal “1”
• Washer “2”
• Circlip “3”
TIP
• Apply is lithium-soap-based grease on the oil
seal lip.
• Install the oil seal in parallel with its manufac-
ture's marks or numbers facing inward.
EAS1SM5246INSTALLING THE RIGHT CRANKCASE
COVER
1. Install:
• Dowel pin “1”
• O-rings “2”
• Collar “3”
• Gasket “4”
TIP
Apply the lithium-soap-based grease on the O-
ring.2. Install:
• Right crankcase cover “1”
• Right crankcase cover bolt “2”
TIP
• Apply the engine oil on the impeller shaft end.
• Mesh the impeller shaft gear “3” with primary
drive gear “4”.
• Tighten the right crankcase cover bolts in
stages and in a crisscross pattern.
New
New
3
2
1
LS
New
New
1
1 4
2
New
New
3
LS
Right crankcase cover bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
T R..
3
1
4
E
12

CLUTCH
5-41
EAS1SM5247INSTALLING THE CLUTCH
1. Install:
• Push lever shaft “1”
TIP
• Apply the lithium soap base grease on the oil
seal lip.
• Before installation, apply the engine oil to the
push lever shaft sliding surface.
2. Install:
• Primary driven gear “1”
• Thrust washer “2”
• Clutch boss “3”
TIP
Apply the engine oil on the primary driven gear
inner circumference.
3. Install:
• Lock washer “1”
• Clutch boss nut “2”
ECA1DX1020
NOTICE
Make sure to tighten to specification; other-
wise, it may damage the other part that is
fastened together.
TIP
Use the clutch holding tool “3” to hold the clutch
boss.4. Bend the lock washer “1” tab.
5. Install:
• Friction plate “1”
• Clutch plate “2”
• Cushion spring “3”
TIP
• Install the clutch plates and friction plates al-
ternately on the clutch boss, starting with a
friction plate and ending with a friction plate.
• Install the cushion spring “3” in the position as
shown.
• Apply the engine oil on the friction plates and
clutch plates.
Clutch boss nut
75 Nm (7.5 m·kgf, 54 ft·lbf)
1
New
T R..
Clutch holder
90890-04086
YM-91042
3
21
1
1
1
2 2
2
1
2
3